The present invention relates generally to a crop spraying apparatus and more particularly to a hydraulically controlled spray boom apparatus.
A typical technique for spraying liquid chemicals such as fertilizers and insecticides to crops uses an applicator vehicle having a storage tank mounted thereon. A spray boom is mounted either on the applicator vehicle or on a tractor pulling the applicator vehicle. This spray boom has a number of spray nozzles mounted thereon in a series relationship. A pump is generally attached to the tractor by the use of a power take-off coupler and torque-arm assembly for transferring the chemical from the storage tank to the spray nozzles, thereby expelling the liquid from the nozzles in a spray form.
The applicator vehicle is typically a two wheel or tandem axle trailer which is towed by a tractor. Past experience has shown that the mounting of all or part of the equipment directly on the tractor generally is not desirable. This is partially because of the increased time required for the mounting and removing of the equipment from the tractor. Furthermore, with the spraying equipment on the tractor, its use for other purposes is severely limited.
With the increase in the amount of land being tilled by the average farmer, there is a definite need to increase the efficiency of the farmer, thereby increasing the amount of land which can be tilled per hour. In the past few years, this has been brought about in the crop spraying art by simply increasing the length of the booms, thereby, increasing the area covered in a single trip across the field.
However, a number of problems are encountered when the booms become of excessive length. Since it is necessary to move the spraying apparatus from one field to another, the spraying equipment must be able to pass through typical farm gates and travel upon public roads. Therefore, the spray booms must be movable to a position different from their normal spraying position, otherwise the apparatus would not pass through gates or be able to travel upon public roads.
Various arrangements have been devised to stow the boom for road travel. However, these structures all have certain drawbacks which make road travel difficult. For example, raising the booms to a vertical position prevents the vehicle from traveling under low hanging objects such as power lines and bridges. Swinging the booms to the rear of the implement creates a serious hazard to other vehicles on the road, while also impairing maneuverability of the implement. Further, removing the booms from the implement for transporting from place to place is undesirable because it is time consuming. Swinging the booms forwardly and inwardly along the vehicle is also often undesirable because many times the overall length of the boom is greater than the length of the vehicle. In such cases, the booms often extend beyond the front of the vehicle to seriously interfere with the maneuverability of the tractor. In some cases, booms have been designed which swing inwardly along side the vehicle as the boom is raised thus making it possible for it to pass over or be positioned above the rear tires of the tractor in a transport position. However, this latter design may present a serious safety hazard to the operator of the tractor, since the tractor many times has to turn sharply and maneuver in tight areas. Further, if the booms are not lifted, they must extend past the outer sides of the oversized tires which are usually used on a spraying vehicle. This results in a lateral width which is hazardous for road travel as well as further reducing the maneuverability of the tractor.
Another problem associated with booms when they are of considerable length involves the instability of the outboard ends of the boom. The vehicles carrying the booms, under normal operating conditions, will encounter ruts, holes, contour terraces and the like, causing uneven travel of the vehicles. This results in jarring and whipping of the boom, which will disrupt the application rate of the liquid and possibly damage the booms. The problem may be solved when shorter booms utilized or when the tank carrying vehicle is operated at a lower speed, but both of these conditions will decrease the efficiency of the farmer.
Often times it is desirable to quickly change the height of the boom while passing over the plants. The need for the change is brought about by a change in the contour of the land and/or different corn heights. Presently, the common methods available for accomplishing this involve a time consuming task of manually readjusting the brackets supporting the boom, thereby physically moving the boom to the desired height.